BULLETIN FLORIDA STATE MUSEUM


curring mainly in the artificial freshwater marsh habitat of active and
inactive clay settling ponds. Wildlife use of this habitat is documented
by Wenner and Marion (1981), Maehr (1980), and Gilbert et al. (1981).
 An even greater threat to both productivity and wildlife potential of
post-reclamation soils is suggested by long-term trends in the nature of
surface soils resulting from mining. Table 15 shows that in 20 years most
reclaimed surface may be sand instead of overburden, resulting in a loss
of both wildlife potential and productive agricultural uses. During the
1970s, the desirable overburden has been the dominant surface soil, av-
eraging 72.4 percent (with 1977 data missing). Moreover, the vast major-
ity of this reclaimed overburden has been deep soil. In the 1980's over-
burden surface soil is projected to continue to dominate reclaimed lands,
but most of it will be in the form of a relatively shallow cap over sand
tailings and/or clay. In the following two decades overburden will dimin-
ish to a small minority of the reclaimed surface. Contributing factors to
this pattern are the use of large amounts of overburden to construct set-
tling pond dikes and the lesser depth of overburden in new mines in the
southern part of the district. The change complementary to the decline
of overburden is the projected increase in sand tailings surface soil from
11.5 percent in the 1970s to 68.1 percent during 2000-09. If that soil is
a sand-clay mix, as proposed, the value of the reclaimed soil may be
quite high. However, if the mixing process continues to be unfeasible or
uneconomical, most reclaimed lands will be dewatered clay surfaced with
low-quality sand tailings.
 The ability of sand tailings to support wildlife habitat, grazing, agri-
culture, and silviculture needs to be investigated. Small mammal com-
munities on early seral tailings are low in diversity and abundance (Mar-
ion et al. 1981). Fertility of sand tailings is relatively low. This soil consists
of about 99 percent sand and 1 percent clay; it is high in CaO and P0,,
but deficient in MgO and K20 (Hawkins 1979). Like other post-mining
soils, sand tailings also is very low in nitrogen. We have examined both
patchy and complete-cover pastures on sand tailings but do not know
whether pasture is difficult to establish or whether cattle stocking levels
need to be low to prevent overgrazing. A citrus planting on sand tailings
between Bartow and Winter Haven failed to survive (Hawkins 1979).
Successional patterns on sand tailings are unknown but are likely to lead
to a xeric plant association, like native longleaf pine savanna, sand pine
forest, or rosemary (Ceratiola) desert, or else to a scrub oak forest in the
absence of fire (Veno 1976).

 INFORMATION GAPS

 A substantial number of information gaps prevent a complete evalua-
tion of the capability of mined land to support wildlife populations and


VOL. 30 NO. 3